The present invention relates, generally, to a Hooke's joint having a spider which, via an anti-friction bearing, connects the fork arms of two articulation forks.
Hooke's joints are generally known and may be found, for example, in German Pat. No. AS26 07 515. Generally, in heavy machine construction such as rolling mills, universal joint shafts are not subjected to extremely high speeds of rotation. However, they are subjected to particularly high moments of rotation and variations in the moments of rotation. They are also subjected to pulsating stresses and transverse accelerations with large rapid changing angles of bending from one portion of the joint to another. Therefore, loads generally result in deformations of the form in the region of the flanges and also in the bores of the fork. These deformations are taken up by anti-friction-type bearings. As the bore within which the pin of the spider gear is disposed, widens, it begins to assume a non-circular shape. This deformation is transmitted to adjacent bearings. This therefore results in the eventual destruction of the cap with the rolling elements of the associated bearings being thrown out of joint or displaced. It has been found that anti-friction bearings do not generally fall as a result of insufficient load capacity but as a result of non-uniform distribution of load over the bearings or as a result of an excessively high percentage of load in given zones of the bearing. More particularly, when a thrust bearing is arranged at the root or base of the pin of a spider gear and therefore radially inward of the radial bearing, the bearing rests directly on a corresponding surface of the base of the pin. Therefore, as a result of bending of the pin, which results in corresponding edge pressures and local lifting off of the rollers in the area of the thrust bearing, errors in alignment result in the radial and thrust bearings. Further, the thrust bearing rings do not participate in this deformation of the pin and cannot threfore move into a position which assures optimum distribution of load over the rollers. Accordingly, the bearing will generally fall long before its calculated or designed life.